Shares of Biogen, Elan fall after Tysabri shows liver risks

WASHINGTON - Shares of Biogen Idec and Elan Corp. fell Wednesday after the companies reported some patients suffered liver injury after taking the drug Tysabri, a treatment for multiple sclerosis and Crohn's disease.

Matthew Perrone/Associated Press

WASHINGTON - Shares of Biogen Idec and Elan Corp. fell Wednesday after the companies reported some patients suffered liver injury after taking the drug Tysabri, a treatment for multiple sclerosis and Crohn's disease.

The companies issued a warning to doctors that signs of liver injury appeared in patients as early as six days after first taking Tysabri.

The Food and Drug Administration posted the companies' letter to physicians online and said patients with any signs of liver damage should stop taking the drug immediately. Regulators updated the product's labeling to highlight liver risks last month, when it was approved for the new use in the intestinal disorder Crohn's Disease. The new language instructs doctors to tell patients about the liver problems.

A spokeswoman for Cambridge, Mass.-based Biogen said the company sent the letter to 2,500 physicians who prescribe the drug for multiple sclerosis, and may not have seen the updated labeling. She said liver problems have been reported by less than one in 1,000 Tysabri patients.

The drug posted sales of $343 million for Biogen last year.

Banc of America Securities analyst William Ho said the announcement was "old news," pointing out that liver problems with Tysabri were revealed at a meeting before FDA's expert advisers last year. They ultimately voted in favor of approving the drug for Crohn's Disease. Ho maintained a "Buy" rating for Biogen's stock with a one-year price target of $73.